YOSEMITE NATIONAL PARK, Calif., Aug. 14 (UPI) -- Two youngsters were killed in Yosemite National Park early Friday when a dead tree branch fell onto their tent as they slept, authorities said.
The children, who were not immediately identified, were asleep in the popular Upper Pines Campground in Yosemite Valley when the branch from an oak tree fell at around 5 a.m. local time Friday, officials said.
By the time park rangers arrived to provide medical assistance, the children were already dead, the National Park Service said.
The cause of the accident is being investigated by park officials.
The U.S. Forest Service said earlier this year that about 12 million trees in Yosemite have died off due to California's ongoing four-year drought.
"Our thoughts are with the families as they grieve this tragedy," Yosemite Superintendent Don Neubacher said Friday.
The accident is reminiscent of a similar accident that occurred at the park in January 2012, when a park employee was killed by a large branch that struck his tent.
"Fallen branches like this one are a common occurrence across the park," a park spokesman said.
Two people died in 1985 when a large branch fell onto an open-air tour bus in the park. The exact same thing happened seven years later in 1992, injuring seven, the Los Angeles Times noted.
Yosemite, which turns 125 years old this year, is an extremely popular park with visitors. Officials say about 500,000 people typically visit in the peak month of August each year.
